Answers

• 
  What is the difference between rebars without E and with E?

  Those marked with "E" must meet two requirements:
  1. The ratio of the measured tensile strength to the measured yield strength must not be less than 1.25;
  2. The ratio of the measured yield strength to the standard yield strength must not be greater than 1.30;

  
  

  Production requirements: If compared with ordinary rebar, if it has an E it means it is an earthquake-resistant rebar that can meet all the performance indicators of ordinary rebar and also achieve an earthquake-resistant effect. Comparing its tensile strength to yield strength ratio, it cannot be less than 1.25. The maximum total elongation of the rebar cannot be less than 9%.
  
  Different characteristics: without E, it is the ordinary type, but with E, it is the earthquake-resistant type. The essential difference is that the ductility of the rebar is more prominent, and it can have better deformation resistance and plasticity during earthquakes.
  
  Different structure: Compared with ordinary rebar, this rebar with E has earthquake-resistant properties. Even if the house is hit by an earthquake shock wave, it will not collapse completely within a certain period of time, which can improve its earthquake resistance.

  
  
• 
  What standards does S690QL steel plate comply with?

  European standard S690QL high-strength plate is a high-quality structural steel.
  Grade: S690QL
  Applicable standard: EN 10025-6
  1. High Strength: European standard S690QL high-strength plate has a tensile strength of 690 MPa, with high yield strength and elongation, effectively improving the load-bearing capacity and seismic performance of structures.
  2. Excellent mechanical properties: The material has excellent fatigue resistance, impact resistance and low temperature resistance, and can maintain stable performance under complex environmental conditions.
  3. Good welding performance: S690QL high-strength plate has good welding performance, is easy to process and connect, and can meet the construction requirements of various complex structures.
  4. Long life: Due to its excellent corrosion resistance and fatigue resistance, S690QL high-strength plate has a long service life, which can greatly reduce the maintenance cost of the building.

  
  

  S690QL is a high-strength alloy structural steel plate that belongs to the European standard (EN 10025-6) special alloy structural steel with excellent mechanical properties and a wide range of applications. The chemical composition of S690QL is carefully formulated to meet its high strength and toughness requirements.
  
  The main element contents (maximum %) include:
  C: ≤0.20%; Si: ≤0.80%; Mn: ≤1.70%; P: ≤0.020%; S: ≤0.010%; Cr: ≤1.50%; Ni: ≤2.00%; Mo: ≤0.70%; Cu: ≤0.50%; V: ≤0.12%; Nb≤0.06%,
  The content and ratio of these elements are crucial to ensuring the overall performance of the steel plate.
  
  Mechanical Properties of S690QL:
  Yield Strength: σ0.2 ≥ 690 MPa (Some sources indicate a yield strength range of 690-890 MPa, but the lower limit of EN 10025-6 is generally followed).
  Tensile Strength: σb 770-940 MPa
  Elongation: ≥ 14%
  Low-Temperature Impact Resistance: Longitudinal V-shaped impact energy ≥ 30J at -40°C
  These mechanical properties enable S690QL steel to withstand high-intensity and heavy-load environments while maintaining excellent toughness and impact resistance.
  
  S690QL steel plate offers the following performance advantages:
  Ultra-high strength: Yield strength ≥ 690 MPa, tensile strength up to 940 MPa, enabling lightweight structures.
  Excellent low-temperature toughness: -40℃ impact energy ≥30J, suitable for extremely cold areas or low-temperature impact conditions.
  Good welding performance: low-temperature impact energy of weld and fusion line> 60J, supporting arc welding, submerged arc welding and other processes. Strong fatigue resistance: low crack growth rate under dynamic load, extending equipment life.
  Corrosion resistance: Surface treatment (such as hot-dip galvanizing and spraying anti-corrosion paint) can further improve corrosion resistance.

  
  
• 
  What are the main aspects of rebar testing?

  1. Chemical Composition Testing: Detects the content of various elements in rebar, such as carbon, silicon, manganese, phosphorus, and sulfur.
  
  2. Mechanical Properties Testing: Test items assessing the mechanical properties of rebar include tensile testing (tensile strength, yield strength, and elongation) and bend testing (single and reverse bend).
  
  Bending performance: After being bent 180 degrees according to the specified bending diameter, no cracks shall appear on the surface of the bent part of the steel bar.
  Reverse bending performance: According to the requirements of the purchaser, the steel bars can be subjected to reverse bending performance tests. The bending center diameter of the reverse bending test is one steel bar diameter larger than that of the bending test. First bend forward 90 degrees, then bend backward 20 degrees. After the reverse bending test, no cracks shall occur on the surface of the bent part of the steel bar.
  
  3. Dimensional and Appearance Inspection: Measure the diameter, length, thread parameters, and other dimensional indicators of the rebar, and inspect its appearance for defects, cracks, and other issues.
  
  4. Surface Quality Inspection: Detect defects such as oxide layers, rust, and scratches on the rebar surface.